1. Field of the Invention
The present invention relates to an inkjet printing apparatus and an inkjet printing method, and particularly to an inkjet printing apparatus and an inkjet printing method which are suitable for producing a print object excellent in glossiness.
2. Description of the Related Art
The inkjet printing method flies small droplets of ink and attaches the small droplets on a print medium such as paper to perform a print and has been widely used even in the field of a high-fineness print owing to a recent technical advance. In recent years, pigment ink excellent in a light resistance, a gas resistance, a water resistance and the like has been increasingly used. In a case where a print is performed with pigment ink on a print medium having a smooth surface, such as an inkjet glossy paper developed for obtaining high-fineness image quality similar to that of a silver halide photography, there occurs a problem that coloring or glossiness of a print portion in the print medium is damaged by diffused reflection of light due to pigment particles in the pigment ink.
For solving this problem, methods of coating a print object with a transparent resin have been developed. For example, in an inkjet printing method described in Japanese Patent Application Laid-Open No. 2006-272934, an application amount of clear ink is determined in accordance with an application amount of pigment ink. In this printing method, the clear ink application amount is reduced on a portion of the print object in which the pigment ink application amount is large and the clear ink application amount is increased on a portion of the print object in which the pigment ink application amount is small, thus making a sum ink application amount per unit area on the entire print object uniform. This method has an object of realizing homogenization in glossiness on the print object.
According to the study of the inventors, however, it is considered that permeability of the clear ink and a remaining state of the clear ink on a surface layer of the resin component differ depending on the kind of the pigment ink and simply making the sum ink application amount per unit area uniform is not sufficient to prevent occurrence of gloss variations. In addition, on the portion to which the pigment ink is applied by a predetermined amount (target amount of the sum ink application amount), the clear ink is not applied, and the glossiness of the pigment ink itself can not be increased. When the clear ink is excessively applied to a pigment ink applying portion, the clear ink remains more than necessary, thereby degrading glossiness. Therefore, it is considered that the clear ink is not applied on the portion to which the pigment ink is applied by a predetermined amount.
The present invention is made in view of the foregoing problem and an object of the present invention is to provide an inkjet printing apparatus and an inkjet printing method which can produce a print object which is excellent in glossiness in its entirety and has largely reduced gloss variations.